OBJECTIVES: 1) Further investigations of the biochemical defect and the effect of dietary therapy in a five year old retarded patient with sulfite oxidase deficiency; 2) Investigations of a patient with a rare and little understood disorder, urocanic aciduria; 3) Study of a patient with hyperglutamic aciduria and possibly formiminoglutamic aciduria; 4) Studies of enzyme defects in skin fibroblasts derived from patients with hyperornithinemia; 5) Continued effort in the identification of the enzyme defect in a "new type of galactosemia;" 6) Development of a simple screening test for galactose metabolic disorders including galactose-1-phosphate uridyl transferase deficiency, galactokinase deficiency and epimerase deficiency; 7) Biochemical and clinical evaluation of the treatment for patients with various metabolic disorders including hyperprolinemia, maple syrup urine disease, phenylketonuria, homocystinuria, argininosuccinic aciduria and galactosemia; 8) Continued effort in the attempt to identify an unknown sulfur-containing metabolite in a mentally retarded patient. BIBLIOGRAPHIC REFERENCES: Shih, V.E.: Congenital hyperammonemic syndromes. Clinics in Perinatology, 3: 3-14, 1976. Shih, V.E.: Errors of organic acid metabolism in HANDBOOK OF BIOCHEMISTRY, third edition, Ed. by G.D. Fasman, CRC Press, Cleveland, 1976, p. 326.